1. Field of Invention
The present invention relates to a latch-up protection circuit for LCD driver IC. More particularly, the present invention relates to a latch-up protection circuit for LCD driver IC comprising an NMOS, a switch and a capacitor.
2. Description of Related Art
The design of the LCD driver IC in the electronic devices is an important issue. Different design styles result in different area sizes, different costs and different performances. Thus, the overall performance of an driver IC highly depends on the design of the driver IC.
The driver IC are easy to suffer from the effect of the noise signal, e.g. electrostatic discharge or rush current. The noise or rush current will make the potential of some parts of the circuit become an extremely high positive voltage level. The high positive voltage level results in the latch-up of the circuit and further results in the malfunction of the circuit. The conventional design of the latch-up protection circuit for LCD driver IC is to use an external schottky diode to connect to a most negative part of the p-substrate of the driver IC that may suffer from the electrostatic discharge and limit these parts of the driver IC in a certain voltage level. But in order to make the production cost down, an electric circuit with less external elements is preferred.
Accordingly, what is needed is a new design of the latch-up protection circuit that can be adapted in the LCD driver IC to prevent the electric circuit from the noise or rush current to overcome the above issues. The present invention addresses such a need.